Cell proliferation of the nornal human thymus-derived lymphocyte is dependent upon the presence of multiple signals. The first component is provided by an antigen (or lectin) with the second being derived from monocyte (Interleukin-1, IL-1). These two agents interact with the human T-cell to eventuate in a mitogenic response. The mechanism by which an antigen and IL-1 results in the proliferative response is thought to be due to a third, T-cell derived signal, termed Interleukin-2 (IL-2). IL-2 has been demonstrated to act as the ultimate mitogenic signal for the actual induction of T-cell proliferation. These signals provide a unique system by which to isolate Go quiescent, Go/G1 activated, G1 progressive and log-phase normal T-cells. This celly cycle control will allow for the effective study of the early events in the induction of T-cell proliferation. Further, they provide an effective system for the isolation of relatively cell cycle specific normal cell populations for comparison with malignant T-cells (represented by cell lines CCRF-CEM and CCRF-HSB-2) in known cell cycle states. These cell systems will be utilized to explore the role of specific subsets of nonhistone chromosomal proteins in respect to the induction of cell proliferation and progression of cells through the early stages of the cell cycle. Experiments will also be conducted to examine more explicitly the nature of cell cycle control in the normal T-cell exposed to the proliferative signals. These studies will include an examination of the nature of T-cell subset selectivity to the Interleukin signals with the goal to further understand cell cycle related events occurring during the induction of growth.